H Biology Midterm Study Guide

Midterm Transfer Task

  • Overview: Transfer tasks challenge students with new phenomena while applying learned science practices to demonstrate knowledge of biology, focusing on content from "Africa" and "Homeostasis."

Science Practices Utilized on the Midterm

  • Application of Data Table and Graphing

    • Inference of what the data is indicating.

  • Analysis of Graphs/Figures

    • Understanding the implications of the graphs and figures.

    • Ability to make predictions based on the presented data.

  • Constructing Explanations

    • Explanation of the impacts of density-independent factors on ecosystems.

  • Argument from Evidence

    • Construction of specific claims defended by sound evidence and reasoning.

Key Concepts and Core Ideas on the Midterm

  • Big Ideas:

    • Ecology

    • Energetics

    • Genetics

    • Evolution

Specific Concepts

  • Predator/Prey Relationships

    • Implications of hunting energetics.

  • Food Webs

    • Connections between multiple organisms and energy flow.

  • Biotic vs. Abiotic Factors

    • Distinction and examples of both types of factors.

  • Carrying Capacity

    • Definition as the maximum population size an environment can sustainably support.

    • Density-dependent Factors:

    • Influences on carrying capacity that change with population size.

    • Density-independent Factors:

    • Examples include natural disasters that affect populations regardless of size.

  • Trophic Levels

    • Energy transfers within ecosystems and the role of producers, consumers, and decomposers.

  • Direct and Indirect Relationships

    • How species interact in ecosystems, such as through competition or symbiosis.

  • Photosynthesis and Cellular Respiration

    • Functions of mitochondria (cellular respiration) and chloroplasts (photosynthesis).

  • Nutrient Cycles

    • Focus on carbon and nitrogen cycles.

  • Homeostasis

    • Mechanisms organisms use to maintain stable internal conditions.

  • Keystone Species

    • Species that have a disproportionately large effect on their environment relative to their abundance.

  • Energy Calculations

    • Mathematical approaches to quantify energy flow and storage.

  • Genetics and Geography

    • How geographical factors influence genetic diversity.

  • Ecosystem Dynamics

    • The concurrent interaction of biotic and abiotic elements in ecosystems.

Cross-Cutting Concepts

  • Patterns

  • Cause and Effect

  • Scale, Proportion, and Quantity

  • Systems

  • Energy and Flow

  • Structure and Function

  • Stability and Change

Ecological Levels & Ecosystems

  • Definitions:

    • Distinction between organisms, species, and populations clarifies ecological processes.

    • An ecosystem comprises both biotic (living) and abiotic (non-living) components.

    • Community-level interactions arise from multiple species responding to environmental changes.

  • Influences on Population Trends:

    • Habitat quality and forage availability adversely affect herbivore populations.

  • Adaptations:

    • Example: Physical adaptations (e.g., thick fur) support survival in specific climates.

  • Predation Effects:

    • Hunting strategies (e.g., group hunting) increase predator efficiency and enable capturing larger prey.

    • Predation shapes prey distribution as a biotic factor.

    • Interaction of abiotic stressors (e.g., severe winters) and biotic factors (predation) influences population sizes.

  • Energy Transfer:

    • Producers convert sunlight into chemical energy and transfer energy upwards in food chains.

    • A decrease in producer populations corresponds to a decline in herbivore populations.

    • Removing top predators alters the roles of secondary and tertiary consumers.

  • Dietary Flexibility:

    • Omnivory enhances resilience in fluctuating environments.

  • Trophic Cascades:

    • Shift in prey behavior due to predator presence can trigger cascading effects through ecosystems.

Interactions, Niches, and Carrying Capacity

  • Territorial Competition:

    • Territorial disputes might drive populations into less suitable habitats.

    • Overlapping feeding niches can lead to interspecific competition.

  • Producer Declines:

    • Reduction in primary producers negatively affects herbivore populations, subsequently influencing predator levels indirectly.

  • Keystone Species:

    • These species exert considerable influence on multiple trophic levels and the overall structure of the ecosystem.

  • Density-independent Factors:

    • Factors such as wildfires and storms affect populations without regard to their numbers.

  • Population Dynamics:

    • Populations typically experience an initial exponential growth phase but later stabilize at their carrying capacity.

    • Logistic growth patterns illustrate that population growth slows as resource scarcity becomes evident.

  • Natural Selection:

    • Favors traits that enhance survival, such as endurance in response to environmental challenges.

  • Genetic Drift:

    • Alters allele frequencies in populations post random events.

Genetics & Evolution

  • Parentage Analysis:

    • Used to determine which individuals contribute genes to future generations.

  • Alloparenting:

    • Involves multiple caregivers, increasing offspring survival.

  • Karyotyping:

    • Technique to identify chromosome numbers and detect chromosomal abnormalities.

  • Role of Alleles:

    • Influence phenotype expression, evident in traits such as coat color.

  • DNA Analysis:

    • Assesses genetic diversity within populations.

  • Genotype–Phenotype Relationships:

    • Clarification on how different alleles lead to varying traits.

  • Microsatellites (STRs):

    • Useful for identifying fine-scale genetic variation within populations.

  • Phylogenetic Trees:

    • Illustrate evolutionary relationships between populations, with nodes indicating common ancestors.

    • Branch lengths represent evolutionary change over time.

Anatomy, Physiology & Feeding

  • Digestive Anatomy:

    • Differences between herbivores and carnivores exemplified by varying gut structures (large cecum for herbivores, small for carnivores).

  • Dentition Patterns:

    • Reflect adaptations to feeding habits: sharp canines for carnivorous diets and flat molars for herbivorous diets.

  • Dental Formulas:

    • Provide insights into an organism's dietary preferences and adaptive strategies.

  • Nutritional Needs of Predators:

    • High energy demands necessitate reliance on proteins and lipids.

  • Biochemical Tests:

    • Biuret Tests: Utilized to detect proteins in prey.

    • Grease-spot Tests: Employed to detect lipids, especially relevant for understanding scavenger diets.

  • Glucose Measurement in Plants:

    • Indicates energy availability and its subsequent influence on herbivores.

Data Collection in Ecology

  • Types of Data in Ecology:

    • Quantitative Data: Employs measurable numerical values (e.g., population size).

    • Qualitative Data: Involves descriptive observations to explain ecological trends.

  • Disturbances:

    • Events like wildfires are classified as density-independent factors that can impact ecosystem structures.

  • Population Growth Trends:

    • Herbivore populations may grow rapidly with abundant resources and limited predation.

  • Carrying Capacity Importance:

    • Helps in predicting population growth trends over time, particularly when resources become constrained.

Energy Flow & Biogeochemical Cycles

  • Photosynthesis Process:

    • Converts atmospheric carbon dioxide (CO₂) into sugars, storing carbon within biomass.

  • Cellular Respiration:

    • Exothermic process that releases carbon dioxide when energy is extracted from food.

  • CO₂ Impact:

    • Increased atmospheric carbon dioxide alters chemical compositions in aquatic ecosystems.

  • Nitrogen Fixation:

    • Converts atmospheric nitrogen into forms usable by plants, crucial for ecosystem functioning.

  • Photosynthesis Reduction Effects:

    • Lowered photosynthesis rates diminish carbohydrate availability, adversely impacting herbivore populations.

  • Overgrazing Outcomes:

    • Results in reduced vegetation cover when herbivores exceed an ecosystem's carrying capacity.

    • Post-grazing vegetation recovery improves habitat conditions for other species, exemplifying community dynamics.

Evolutionary Evidence & Behavioral Ecology

  • Homologous Structures:

    • Structural similarities in anatomy that illustrate shared ancestry among species.

  • Cooperative Hunting Strategies:

    • Increase the success rate of predators capturing larger prey, a behavior affecting population dynamics.

  • Natural Selection and Advantageous Traits:

    • Traits such as thick fur or effective digestive mechanisms are preserved through natural selection due to the advantages they confer in survival.

Mammalian Dive Response

  • Triggering Conditions:

    • Activated upon immersion of the face in cold water.

  • Physiological Responses:

    • Key responses include bradycardia (slowing of the heart rate), peripheral vasoconstriction (narrowing of blood vessels), and blood shift (redistribution of blood to vital organs during dives).

  • Purpose:

    • Conserves oxygen and energy while submerged, enhancing survival in aquatic environments.

  • Response Strength:

    • Aquatic mammals exhibit the most pronounced dive responses among species.

Photosynthesis

  • Energy Conversion:

    • Converts light energy into chemical energy in the form of glucose.

  • Cellular Location:

    • Takes place in chloroplasts within plant cells.

  • Light-Dependent Reactions:

    • Capture sunlight, resulting in ATP and NADPH production.

  • Calvin Cycle (Light-Independent Reactions):

    • Utilizes ATP and NADPH to synthesize sugars, forming the basis for food webs and the carbon cycle.

Cellular Respiration

  • Energy Conversion Process:

    • Converts glucose into ATP (adenosine triphosphate), the energy currency of cells.

  • Cellular Location:

    • Occurs in mitochondria of eukaryotic cells.

  • Steps Involved:

    • Involves glycolysis, the Krebs cycle, and the electron transport chain.

  • Outputs of Cellular Respiration:

    • Produces carbon dioxide (CO₂), water, and ATP, enabling movement, growth, and all cellular functions.